SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '60baa68385f0bc50ee1e72809920670428a431998ee2c16486420af807bc1a8d' 
  AND token = 'vE8nAymwdpUxtKopWgPjLHyRwt6PXHZ5F+d1lwuPL/w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}